Self-propelled endoscopic device

ABSTRACT

An endoscopic device for autonomous locomotion through a body cavity with a predetermined direction, the device comprising a tubular body constructed of a relatively elastic material that extends between two, preferably, the front and rear, end portions, respectively. The tubular body includes an anchor for temporarily and alternately attaching the end portions to a wall portion of the body cavity in synch with corresponding axial extensions and contractions of the tubular body. The tubular body incorporates a reinforcement structure distributed along its length that is substantially rigid in a radial direction and yields in an axial direction, the structure specifically comprising either a plurality of relatively rigid rings or at least one helical spring.

FIELD OF THE INVENTION

The present invention relates generally to medical devices and, moreparticularly, to a device suitable for locomotion through a body cavity.

BACKGROUND OF THE INVENTION

Endoscopic devices are typically used by surgeons for a variety ofsurgical and/or diagnostic procedures. In operation, a surgeon appliesmanual force, for instance, directly to the device in order to impartforward motion of the device through a patient's body. Such devices areusually operated in conjunction with other surgical and/or diagnosticinstruments, e.g., micro-arms, micro-cameras and/or laser emitters, thatmay be needed to complete various medical procedures.

Endoscopic devices for surgical or diagnostic procedures are alreadyknown, which are operated by the surgeon who directly imparts to thedevice its forward motion through the patient's body. These devices aregenerally associated with surgical and/or diagnostic instruments neededto complete various procedures, e.g. micro-arms, micro-cameras and/orlaser emitters.

Endoscopic devices of this type, but capable of autonomous orsemi-autonomous locomotion through the body cavity of a patient aredescribed, for instance, in U.S. Pat. No. 5,398,670, U.S. Pat. No.5,906,591 and WO02/068035. The endoscopic device described in thesedocuments substantially consists of a tubular body of variable lengthwith two, front and rear end portions, complete with anchoring meansthat enable said front end portion or rear end portions to becometemporarily and alternately attached to the wall of the body cavity,thereby enabling the forward motion of the device.

In particular, the variable-length tubular body of the endoscopic devicedescribed in the above-mentioned documents is in the form of abellows-shaped tube and is consequently capable of being extended orcontracted by means of air injected therein or aspirated therefrom. Inthe above-mentioned patent application PCT n. WO02/068035, the device isanchored to the wall of the body cavity by clamping means associatedwith the front and rear end portions of the device and selectivelyenabled by an external control unit in synchronism with the successiveextensions and contractions of the bellows-shaped tubular body. Theaforementioned clamping means are enabled by pneumatic actuating meansthat, in the preferred embodiment of the invention, also consist ofbellows-shaped members.

When it is extended, a positive pressure is created inside the bellowsby means of compressed air, thereby obtaining an elongation proportionalto the pressure therein, while the bellows are contracted byprogressively reducing the pressure inside the bellows, until somedegree of vacuum is created.

Although it has the considerable flexibility needed to negotiate thenarrow intestinal loops without causing pain, the device according tothe above-mentioned PCT patent application has several functionaldrawbacks due to its relative extendibility and friction between itsouter surface and the walls of the body cavity, which have a negativeeffect on the device's efficiency of locomotion. Because the intestinalwalls adhere partially or totally to the outer surface of the bellows,the intestinal tissue may be trapped between the folds of the bellows during the contraction stage. Though it does no damage the mucosa, thisinterferes with the progress of the device through the intestines.Moreover, given the elasticity of the mesentery and intestinal tissues,any friction between the surface of the tubular bellows-shaped body andthe walls of the body cavity will stretch the tissue and mesenteryinstead of making the device slide along the walls, thus preventing anyforward motion of the device relative to the intestinal walls during theextension stage, then allowing the tissues of the tubular cavity and themesentery to return to their original position (with a so-called“accordion effect”) during the contraction stage.

It should be noted, moreover, that the considerable thickness of thebellows-shaped tubular body (in terms of the difference between themaximum radius and the minimum radius of the contracted and extendedbellows) results in a significant reduction in the space actuallyavailable inside it, making difficult the passage of the compressed airtubes needed for the displacement of the device and making it necessaryto use smaller-diameter tubes, with a consequent increase in thepressure drop and reduction in the device's speed of locomotion.

OBJECTS AND SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide aself-propelled endoscopic device that provides the same degree offlexibility as conventional autonomous or semi-autonomous endoscopicdevices, but without hindering the device's efficiency of locomotionduring use.

A particular object of the present invention is to provide an endoscopicdevice of the above-mentioned type wherein the tubular body has aconsiderable capacity for extension and a low friction coefficient so asto avoid any entrainment of the tissues forming the wall of the bodycavity and thus ensure an effective locomotion of the device.

Another particular object of the present invention is to provide anendoscopic device of the aforementioned type with a significantly morespacious interior, while maintaining the same outer diameter, than isavailable in endoscopic devices of known type with bellows-shapedbodies, thereby enabling said interior to be used more efficiently forthe passage of the service tubes.

A further object of the present invention is to provide an endoscopicdevice of the above-mentioned type, wherein its tubular body, or theactuators of the anchoring means provided on its front and rear endportions, will contract without giving rise to any circumferentialsurface folds in which the tissue of the wall forming the body cavitythrough which the endoscopic device is advancing might become trapped.

These objects are achieved by the improved endoscopic device accordingto the present invention, in which its tubular body is made of anelastic material and incorporates a reinforcement structure distributedalong its length that is substantially rigid in the radial direction andyielding in the axial direction. In the preferred embodiments, saidreinforcement consists either of a plurality of substantially rigidrings, or of at least one coaxial spring, or preferably a pair ofsprings wound crosswise to one another, incorporated within itsthickness.

BRIEF DESCRIPTION OF THE DRAWINGS

A specific, illustrative self-propelled endoscopic device, according tothe present invention, is described below with reference to theaccompanying drawings, in which:

FIG. 1 shows schematically a self-propelled endoscopic device, accordingto one aspect of the present invention;

FIG. 2 is an enlarged sectional view of a central tubular body of anendoscopic device, according to another aspect of the present invention;

FIG. 3 is a perspective view of a central tubular body of an endoscopicdevice, according to a further aspect of the present invention;

FIG. 4 is a sectional view taken longitudinally of the central tubularbody shown in FIG. 3;

FIG. 5 illustrates schematically an end portion of an endoscopic device,according to one aspect of the present invention, having an anchor in anopen position; and

FIG. 6 is a schematic illustration of the device shown in FIG. 5 withthe anchor in a closed position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and, more particularly, to FIGS. 1-6,there is shown generally a self-propelled endoscopic device, inaccordance with various aspects of the present invention. According toone embodiment, as set forth in FIG. 1, the device comprises a tubularbody 1 extending between two end portions, referred to generally asfront 2 and rear 3 end portions, respectively, the terms front and rearreferring to the device's direction of locomotion through a selectedbody cavity, as indicated generally by arrow F. In this manner, thedevice is preferably and advantageously moveable in both forward andreverse directions within the body cavity.

The front 2 and rear 3 end portions of the device include anchoringmeans 4, specifically of the clamping type, by means of which the devicetemporarily and alternately becomes attached to the wall of the bodycavity to enable its locomotion in a known manner.

According to the present invention, the tubular body 1 is made of alow-hardness elastomeric material, e.g. Shore A 10 silicone. The tubularbody 1 has a structural reinforcement comprising, in a first embodimentof the invention illustrated in FIG. 2, a plurality of rings 5 made of arigid material, e.g. Shore A 80 silicone.

The rear end portion 3 is connected to an external control unit by meansof a hose 6, which houses the services tubes, including the tubingneeded to deliver compressed air inside the tubular body 1, or to createa negative pressure therein, thereby inducing the extension orretraction of the tubular body 1 that is necessary for the knownso-called inchworm type of locomotion.

In an alternative embodiment of the invention, illustrated in FIGS. 3and 4, the silicone tubular body 1 is reinforced with a pair of helicalsprings 8 and 9 made of a rigid material, e.g. steel, wound crosswise toone another.

In both cases, the presence of the plurality of rings or of the twocoaxial springs prevents any radial dilation or collapse of the tubularbody 1, while still allowing its extension and retraction in the axialdirection according to changes in the internal pressure conditions.

In the case involving a pair of helical springs, 8 and 9, thearrangement of the springs with the windings lying crosswise to oneanother prevents any related rotation of the device's end portions 2 and3 (which would induce a continuous rotation of the image transmitted bya TV camera installed in the front end portion 2) or any twisting of thehose 6 extending from the rear end portion 3. The fact that the twosprings 8 and 9 are wound crosswise to one another also facilitates thesliding of the tissue of the body cavity over the outer surface of thetubular body 1.

Silicone tubing reinforced with rings 5, or a helical spring 10, asillustrated in FIGS. 5 and 6, can also be used for the actuating devicethat controls the opening and closing of the anchoring means 4 installedat the front 2 and rear 3 end portions of the endoscopic device. Asillustrated in the above-mentioned figures, the anchoring means 4comprise a pair of circular jaws 4 a and 4 b, the former of which isfixed, while the latter is movable with respect to the former. Inparticular, the movable jaw 4 b is slidingly mounted on a tubular member11 extending at right angles from a connection flange 13 by means ofwhich the end portion 2 is axially connected to the tubular body 1. Themovable jaw 4 b is also connected to the flange 13 by means of asilicone tube 12 with a helical spring 10 (in the case illustrated)incorporated within its thickness. The tube 12 delimits a chamber 14into which compressed air can be delivered or a negative pressure can becreated through a hole 15 in the tubular member 11. The creation of apositive or negative pressure in the chamber 14 results in the extensionor contraction of the tube 12, which in turn makes the movable jaw 4 bslide one way or the other and, as a consequence, respectively close oropen the anchoring means 4.

The improvement according to the present invention, applied both to thetubular body and to the pneumatic actuators of the anchoring means,ensures an efficient locomotion of the endoscopic device, overcoming allthe above-mentioned drawbacks of the known devices. In fact, the outersurface of the device remains smooth and slippery both in extension andin contraction, without any folds formation in which the tissue of thebody cavity wall could be trapped. Moreover, the absence of the typicalfolds of a bellows design leads to an increase in the ratio of theinternal to the external diameter of the device, affording asignificantly larger internal volume for the same external diameter,which facilitates the passage of the service tubes. Finally, thehighly-extendable tubular body 1 combines with a low frictioncoefficient to prevent any stretching of the body cavity wall tissues,which would slow down the forward displacement of the device reducingits locomotion efficiency.

Various modifications and alterations may be appreciated based on areview of this disclosure. These changes and additions are intended tobe within the scope and spirit of the invention as defined by thefollowing claims.

1. An endoscopic device for self-propelled locomotion through a selectedbody cavity in a predetermined direction, comprising a tubular bodyconstructed of a relatively elastic material extending between two endportions, with an anchor suitable for temporarily and alternatelyattaching the end portions to a selected wall portion of the body cavityin synch with corresponding extensions and contractions axially of thetubular body, and a pneumatic device for actuating the anchor, whereinthe tubular body incorporates a reinforcement structure distributedalong its length that is substantially rigid in a radial direction andyields in an axial direction.
 2. The endoscopic device set forth inclaim 1, wherein the pneumatic device comprises a tubular memberconstructed of a relatively flexible elastic material incorporating thereinforcement structure, joined axially to a moveable member of theanchor and to the tubular body, and capable of extending and contractingcyclically in response to positive and negative pressures created in itsinternal chamber, and thereby effecting respective closing and openingof the anchor.
 3. The endoscopic device set forth in claim 2, whereinthe anchor is of a clamp type, and is formed generally of a fixed jawand a mobile jaw, to which the tubular member is connected.
 4. Theendoscopic device set forth in claim 1, wherein the reinforcementstructure comprises a plurality of substantially rigid rings embeddedcoaxially within the thickness of the tubular body and the tubularmember.
 5. The endoscopic device set forth in claim 1, wherein thereinforcement structure comprises at least one helical springincorporated coaxially within the thickness of the tubular body and thetubular member.
 6. The endoscopic device set forth in claim 5, whereinthe structure for reinforcing the tubular body comprises a pair ofcoaxial helical springs wound crosswise relative to one another.
 7. Theendoscopic device set forth in claim 1, wherein the elastic and flexiblematerial is a low-hardness silicone.
 8. The endoscopic device set forthin claim 1, wherein at least one of the rings is constructed of siliconeShore A 80.